1. Field of the Invention
This invention relates to a tow feeding apparatus. More particularly, it relates to a tow feeding apparatus wherein continuous watching of the tow fed into a case through pinch rolls is made unnecessary, a resetting time of the tow is shortened when the tow winds around the pinch roll, and a safe operation is assured.
2. Description of the Related Art
Melt-spinning of general-purpose synthetic fibers such as those of polyesters, polypropylene, etc. has generally been carried out by extruding a molten polymer through a number of spinning nozzles to obtain a number of filaments, and collecting the filaments in a form of a tow which is then stored in a case.
FIG. 2 shows a schematic view illustrating a conventional apparatus for feeding a tow into a case. In the figure, a number of filaments 2 extended from spinning nozzles 1 are cooled, drawn by a take-up roll 3 and collected to form a tow 4. The tow 4 is then fed into a case 12 via guide rolls 5 by means of pinch rolls, that is a pair of rolls 8 and 9 rotating at a high speed.
The total denier of tow is generally as large as several thousand to several hundred thousand deniers in order to raise productivity. The feeding conditions of pinch rolls 8, 9 have been carefully set by choosing the nip pressure thereof and the speed ratio thereof relative to guide rolls 5 or by choosing spinning oils, etc. However, due to single filament breaks or wrapping of single filaments n the tow around the rolls, wrapping of a tow around the pinch rolls often occurs during operation.
Once wrapping around the pinch rolls 8, 9 has occurred, the pinch rolls 8, 9 are stopped in operation, and then a tow is wound around a winding roll 6 via a tow-passing route E by hand or by an air sucker, followed by removing tow wastes wrapped on the pinch rolls, changing a tow-passing route to a route F by hand, and again starting the pinch rolls as well as stopping the winding roll 6.
According to the conventional apparatus, once wrapping on the pinch rolls 8, 9 has occurred, the pinch rolls have to be stopped in operation and the wrapped tow wastes removed. Further, when the pinch rolls 8, 9 are stopped late, the tow stored in the case may also have become wrapped on the pinch rolls. When wrappings of tow on all rotating bodies occur, all rotating parts such as takeup rolls 3 and guide rolls 5 have to be stopped. For returning such a state to a normal one, it has been necessary to remove the wrapped wastes from the rotating parts. Further, when the time for resetting a tow is prolonged, the extrusion of a molten polymer has to be stopped. Thus, until the resetting has been attained, a rather long time has been required, resulting in the waste of a large quantity of tow. Further, since an extraordinary load has been applied to the gears in the gear box of the pinch rolls due to the wrapped tow, the gears have often been broken. Thus, continuous watching has been required for minimizing the wrapping around the pinch rolls, and much labor has been required for the reset operations, which may be dangerous.